RFC 1877 PPP IPCP Extensions December 1995
Primary and secondary addresses are negotiated independently. They
serve identical purposes, except that when both are present an
attempt SHOULD be made to resolve names using the primary address
before using the secondary address.
For implementational convenience, these options are designed to be
identical in format and behavior to option 3 (IP-Address) which is
already present in most IPCP implementations.
Since the usefulness of name server address information is dependent
on the topology of the remote network and local peer's application,
it is suggested that these options not be included in the list of
"IPCP Recommended Options".
1.1. Primary DNS Server Address
Description
This Configuration Option defines a method for negotiating with
the remote peer the address of the primary DNS server to be used
on the local end of the link. If local peer requests an invalid
server address (which it will typically do intentionally) the
remote peer specifies the address by NAKing this option, and
returning the IP address of a valid DNS server.
By default, no primary DNS address is provided.
A summary of the Primary DNS Address Configuration Option format is
shown below. The fields are transmitted from left to right.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Primary-DNS-Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Primary-DNS-Address (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
129
Length
6
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RFC 1877 PPP IPCP Extensions December 1995
Primary-DNS-Address
The four octet Primary-DNS-Address is the address of the primary
DNS server to be used by the local peer. If all four octets are
set to zero, it indicates an explicit request that the peer
provide the address information in a Config-Nak packet.
Default
No address is provided.
1.2. Primary NBNS Server Address
Description
This Configuration Option defines a method for negotiating with
the remote peer the address of the primary NBNS server to be used
on the local end of the link. If local peer requests an invalid
server address (which it will typically do intentionally) the
remote peer specifies the address by NAKing this option, and
returning the IP address of a valid NBNS server.
By default, no primary NBNS address is provided.
A summary of the Primary NBNS Address Configuration Option format is
shown below. The fields are transmitted from left to right.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Primary-NBNS-Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Primary-NBNS-Address (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
130
Length
6
Primary-NBNS-Address
The four octet Primary-NBNS-Address is the address of the primary
NBNS server to be used by the local peer. If all four octets are
set to zero, it indicates an explicit request that the peer
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RFC 1877 PPP IPCP Extensions December 1995
provide the address information in a Config-Nak packet.
Default
No address is provided.
1.3. Secondary DNS Server Address
Description
This Configuration Option defines a method for negotiating with
the remote peer the address of the secondary DNS server to be used
on the local end of the link. If local peer requests an invalid
server address (which it will typically do intentionally) the
remote peer specifies the address by NAKing this option, and
returning the IP address of a valid DNS server.
By default, no secondary DNS address is provided.
A summary of the Secondary DNS Address Configuration Option format is
shown below. The fields are transmitted from left to right.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Secondary-DNS-Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Secondary-DNS-Address (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
131
Length
6
Secondary-DNS-Address
The four octet Secondary-DNS-Address is the address of the primary
NBNS server to be used by the local peer. If all four octets are
set to zero, it indicates an explicit request that the peer
provide the address information in a Config-Nak packet.
Default
No address is provided.
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RFC 1877 PPP IPCP Extensions December 19951.4. Secondary NBNS Server Address
Description
This Configuration Option defines a method for negotiating with
the remote peer the address of the secondary NBNS server to be
used on the local end of the link. If local peer requests an
invalid server address (which it will typically do intentionally)
the remote peer specifies the address by NAKing this option, and
returning the IP address of a valid NBNS server.
By default, no secondary NBNS address is provided.
A summary of the Secondary NBNS Address Configuration Option format
is shown below. The fields are transmitted from left to right.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Secondary-NBNS-Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Secondary-NBNS-Address (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
132
Length
6
Secondary-NBNS-Address
The four octet Secondary-NBNS-Address is the address of the
secondary NBNS server to be used by the local peer. If all
four octets are set to zero, it indicates an explicit request
that the peer provide the address information in a Config-Nak
packet.
Default
No address is provided.
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